The use of the term 'iFag' refers to someone who is overtly obsessed with an Apple product they own, to the point they will believe anything Apple say right or wrong, dismiss any other tech brand as a viable option and are rather obnoxious human beings.

iFags are people who automatically get influenced by Apple's ads and market sales.
iFags will deny anything you say about any other product or company.
They tend to be selfish and don't give a shit about you or your opinions.
They are an odd type of human.

Guy 1: "Hey dude do you like the Xbox One or the PS4?"
iFag:" Apple is better than xbox"
Guy 1:" I asked which console you think is the best"
iFag: "dude shutup iPhones are better because apple is a rich company"
Guy 1: "Ok.. so what do you think about androids?"
iFag: (Gives 20k illogical and absurd reasons of the screen size) "oh yeah and and also it has a new swipe feature and it has appstore"
Guy 1: "you fucking iFags"

An IFag (IFaggot) is generally anyone who uses only one brand of technology exclusively (i.e. Macintosh, Samsung, HP, Toshiba, ect.); they will generally argue their defense as being their brand is 'better' with no actual factual proof other than slogans or information obtained 'second-hand' from their fellow IFags. This shouldn't be confused with 'ICurious' users who will 'try' new brands or switch between two or more brands in order to see what they find it 'better' at the time. However, this title can be related to exclusive gamers (i.e. XBOX, PS or Nintendo), with other references such as 'gear queer' or 'techno whore'. Generally, these parties on all sides should also be avoided when making choices based on technology for personal use as most of their opinions on the matter are biased and misguided which may make others into IFag or ICurious converts.